Traditionally, lesioning neural tissue has been used to destroy aberrant neural tissue. Lesioning tissue destroys all nerve activity and generally causes collateral damage. While there are a variety of different techniques and mechanisms that have been designed to focus lesioning directly onto the target nerve tissue, collateral damage is inevitable. Even when it is possible to direct all lesioning energy onto the target nerve cluster, it is a significant drawback that other functioning of the nerves is lost. In addition, there are several common side effects to the lesioning described in the medical literature. It is because of the development of these and other side effects, including the poor response of medical or surgical therapy especially after a delay in treatment, that thoracic or lumbar sympathectomy has not enjoyed a greater popularity among physicians.
Currently, various movement disorders, including Parkinson's and essential tremor, are treated by electrical stimulation of the brain with implanted electrodes. Electrical stimulation is also approved for use in the treatment of tremors in refractory Parkinson's. The principle behind these approaches involves disruption and modulation of neuronal circuit transmission at specific sites in the brain. Generally, this is achieved by implanting tiny electrodes at these sites to sense aberrant electrical signals and to send electrical pulses to locally disrupt neuronal transmission.
There is a need in the art to selectively control neuron activity, modulate levels of neurochemicals and endogenous compounds, and to modulate expression of receptors produced by the body. The altered neuronal activity, modulated levels of compounds or expression of receptors can be used selectively, alone, or in combination with pharmacological therapies, to provide enhanced treatment of a patient suffering from various physiological disorders.